Lade Rachel E, Onel Lavinia, Blitz Mark A, Seakins Paul W, Stone Daniel
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
National Centre for Atmospheric Science, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
J Phys Chem A. 2024 Apr 11;128(14):2815-2824. doi: 10.1021/acs.jpca.4c00199. Epub 2024 Mar 29.
Kinetics of reactions between SO and CHCHOO Criegee intermediate conformers have been measured at temperatures between 242 and 353 K and pressures between 10 and 600 Torr using laser flash photolysis of CHCHI/O/N/SO gas mixtures coupled with time-resolved broadband UV absorption spectroscopy. The kinetics of -CHCHOO + SO are pressure-dependent and exhibit a negative temperature dependence, with the observed pressure dependence reconciling apparent discrepancies between previous measurements performed at ∼298 K. Results indicate a rate coefficient of (4.80 ± 0.46) × 10 cm s for the reaction of -CHCHOO with SO at 298 K and 760 Torr. In contrast to the behavior of the -conformer, the kinetics of -CHCHOO + SO display no significant dependence on temperature or pressure over the ranges investigated, with a mean rate coefficient of (1.18 ± 0.21) × 10 cm s over all conditions studied in this work. Results indicate that the reaction of -CHCHOO with SO competes with unimolecular decomposition and reaction with water vapor in areas with high SO concentration and low humidity, particularly at lower temperatures.
利用CHCHI/O/N/SO气体混合物的激光闪光光解结合时间分辨宽带紫外吸收光谱，在242至353 K的温度和10至600 Torr的压力下测量了SO与CHCHOO Criegee中间体构象异构体之间反应的动力学。-CHCHOO + SO的动力学与压力有关，且呈现负温度依赖性，观察到的压力依赖性消除了先前在约298 K下进行的测量之间的明显差异。结果表明，在298 K和760 Torr下，-CHCHOO与SO反应的速率系数为(4.80 ± 0.46) × 10 cm³ s⁻¹。与-构象异构体的行为相反，-CHCHOO + SO的动力学在所研究的温度和压力范围内对温度或压力没有显著依赖性，在本工作研究的所有条件下，平均速率系数为(1.18 ± 0.21) × 10 cm³ s⁻¹。结果表明，在SO浓度高且湿度低的区域，特别是在较低温度下，-CHCHOO与SO的反应与单分子分解以及与水蒸气的反应相互竞争。
